CEM 141
CEM 141 Exam 3 Study Questions and
Answers Graded A+ 2026
change of state from solid -> liquid -> gas ________ energy -Correct Answer ✔-
requires
energy needed to phase change from solid --> liquid --> gas comes from: -Correct
Answer ✔-the surroundings
when phases change from solid --> liquid --> gas, interactions are _______
between molecules -Correct Answer ✔-overcome
change of state from gas --> liquid --> solid ______ energy -Correct Answer ✔-
releases
what happens to the energy from a phase change from gas --> liquid --> solid? -
Correct Answer ✔-released to surroundings
when phases change from gas --> liquid --> solid, interactions are _______
between molecules -Correct Answer ✔-formed
what happens when a substance melts? -Correct Answer ✔-the interactions
between the particles have to be overcome -- so that they can remove relative to
each other (that's what allows a liquid to flow)
melting and boiling points provide an estimate of: -Correct Answer ✔-the strength
of the attractive interactions between particles
which is stronger?? covalent bond/LDF -Correct Answer ✔-covalent bond
in a covalent bond, what is formed? -Correct Answer ✔-a new molecule
what is a LDF caused by? -Correct Answer ✔-fluctuating charge distribution
CEM 141
,CEM 141
covalent bonds are the sharing of: -Correct Answer ✔-valence electrons
LDF's increase with.... -Correct Answer ✔-the size of electron cloud
covalent bonds are caused by: -Correct Answer ✔-attraction between electrons of
one atom and the nucleus of another
LDFs are present where??? -Correct Answer ✔-between all molecular species
is it hard or easy to predict covalent bond strength? -Correct Answer ✔-hard
when are covalent bonds present? -Correct Answer ✔-when atomic orbitals
interact constructively
covalent bonds are located: -Correct Answer ✔-between molecules/networks
LDFs occur between: -Correct Answer ✔-separate molecules
diamond has a high/low melting point??? -Correct Answer ✔-high
graphite has a high/low melting point?? -Correct Answer ✔-high
diamond is hard/soft? -Correct Answer ✔-hard
graphite is hard/soft? -Correct Answer ✔-soft
diamond's physical properties -Correct Answer ✔-brittle, translucent
diamond does/does not conduct electricity?? -Correct Answer ✔-does not
graphite's physical properties -Correct Answer ✔-slippery, shiny, grey
CEM 141
, CEM 141
graphite does/does not conduct electricity? -Correct Answer ✔-does
in diamond, each carbon forms how many bonds to how many carbons??? -
Correct Answer ✔-4 bonds to 4 identical carbons
in diamond, the bonds between carbons arrange themselves towards: -Correct
Answer ✔-the corners of a 4-sided figure (tetrahedron)
what is the C-C-C bond angle in diamond? -Correct Answer ✔-109°
what model of bonding is used to explain the bonding in carbon? -Correct Answer
✔-Valence Bond Theory
Valence Bond Theory -Correct Answer ✔-atomic orbitals overlap to form bonds
how are bonds often shown in the valence bond theory? -Correct Answer ✔-as
"sticks"
in the Molecular Orbital Theory, atomic orbitals combine to form: -Correct Answer
✔-an equal # of molecular orbitals
in MO Theory, each orbital can contain up to ____ electrons -Correct Answer ✔-2
in MO theory, electrons in bonding orbitals (stabilized/destabilized) the system?? -
Correct Answer ✔-stabilized
in MO theory, each bond is made up of how many electrons? -Correct Answer ✔-2
electrons
in MO theory, electrons are localized where? -Correct Answer ✔-the bond
in the Valence Bond Theory, atomic orbitals _____ to form a bond -Correct Answer
✔-overlap
CEM 141
CEM 141 Exam 3 Study Questions and
Answers Graded A+ 2026
change of state from solid -> liquid -> gas ________ energy -Correct Answer ✔-
requires
energy needed to phase change from solid --> liquid --> gas comes from: -Correct
Answer ✔-the surroundings
when phases change from solid --> liquid --> gas, interactions are _______
between molecules -Correct Answer ✔-overcome
change of state from gas --> liquid --> solid ______ energy -Correct Answer ✔-
releases
what happens to the energy from a phase change from gas --> liquid --> solid? -
Correct Answer ✔-released to surroundings
when phases change from gas --> liquid --> solid, interactions are _______
between molecules -Correct Answer ✔-formed
what happens when a substance melts? -Correct Answer ✔-the interactions
between the particles have to be overcome -- so that they can remove relative to
each other (that's what allows a liquid to flow)
melting and boiling points provide an estimate of: -Correct Answer ✔-the strength
of the attractive interactions between particles
which is stronger?? covalent bond/LDF -Correct Answer ✔-covalent bond
in a covalent bond, what is formed? -Correct Answer ✔-a new molecule
what is a LDF caused by? -Correct Answer ✔-fluctuating charge distribution
CEM 141
,CEM 141
covalent bonds are the sharing of: -Correct Answer ✔-valence electrons
LDF's increase with.... -Correct Answer ✔-the size of electron cloud
covalent bonds are caused by: -Correct Answer ✔-attraction between electrons of
one atom and the nucleus of another
LDFs are present where??? -Correct Answer ✔-between all molecular species
is it hard or easy to predict covalent bond strength? -Correct Answer ✔-hard
when are covalent bonds present? -Correct Answer ✔-when atomic orbitals
interact constructively
covalent bonds are located: -Correct Answer ✔-between molecules/networks
LDFs occur between: -Correct Answer ✔-separate molecules
diamond has a high/low melting point??? -Correct Answer ✔-high
graphite has a high/low melting point?? -Correct Answer ✔-high
diamond is hard/soft? -Correct Answer ✔-hard
graphite is hard/soft? -Correct Answer ✔-soft
diamond's physical properties -Correct Answer ✔-brittle, translucent
diamond does/does not conduct electricity?? -Correct Answer ✔-does not
graphite's physical properties -Correct Answer ✔-slippery, shiny, grey
CEM 141
, CEM 141
graphite does/does not conduct electricity? -Correct Answer ✔-does
in diamond, each carbon forms how many bonds to how many carbons??? -
Correct Answer ✔-4 bonds to 4 identical carbons
in diamond, the bonds between carbons arrange themselves towards: -Correct
Answer ✔-the corners of a 4-sided figure (tetrahedron)
what is the C-C-C bond angle in diamond? -Correct Answer ✔-109°
what model of bonding is used to explain the bonding in carbon? -Correct Answer
✔-Valence Bond Theory
Valence Bond Theory -Correct Answer ✔-atomic orbitals overlap to form bonds
how are bonds often shown in the valence bond theory? -Correct Answer ✔-as
"sticks"
in the Molecular Orbital Theory, atomic orbitals combine to form: -Correct Answer
✔-an equal # of molecular orbitals
in MO Theory, each orbital can contain up to ____ electrons -Correct Answer ✔-2
in MO theory, electrons in bonding orbitals (stabilized/destabilized) the system?? -
Correct Answer ✔-stabilized
in MO theory, each bond is made up of how many electrons? -Correct Answer ✔-2
electrons
in MO theory, electrons are localized where? -Correct Answer ✔-the bond
in the Valence Bond Theory, atomic orbitals _____ to form a bond -Correct Answer
✔-overlap
CEM 141
